Young people looking for adventure fiction now generally turn to fantasy, but for those of a certain age the spy thriller has long been the escape reading of choice. Like many teenagers, I devoured the exploits of James Bond, but also those of 007’s American cousins, in particular Donald Hamilton’s Matt Helm ("The Ambushers," "The Intriguers," et al.), Edward S. Aaron’s Sam Durell ("Assignment: Ankara," "Assignment: Sulu Sea," et al.), and Philip Atlee’s Joe Gall ("The Paper Pistol Contract," "The Silken Baroness Contract," et al.). Am I alone in remembering with fondness John Craig in James Munro’s "The Man Who Sold Death" and its three sequels? Of course, for titillation, as well as comic-book style action, one could always rely on Peter O’Donnell’s adventures of the quite literally stunning Modesty Blaise, who could gain the drop on the bad guys by simply entering a room topless.

These books were all very much action-oriented. Not so, the more cerebral thrillers of the 1960s and ’70s. Len Deighton’s "The Ipcress File" introduced a shrewd working-class operative without a name, while John le Carré's "Tinker, Tailor, Soldier, Spy" made espionage almost bureaucratic, a more deadly variety of corporate intrigue. But le Carré was also a master of intricate plot construction, deeply knowledgeable of the tradecraft and technical aspects of spying, and, above all, a superb stylist, in fact a literary author at heart. Most of all, his books were, and are, moral dramas, as well as political ones.

The roots of that deeper kind of spy thriller go back to Erskine Childers’s The Riddle of the Sands (1903). On the back cover of the recent Penguin edition it is no surprise, then, to find a blurb from Le Carré: “Vibrant, impassioned, witty, intelligent and shamelessly prejudiced in the manner of its day, 'The Riddle of the Sands' remains one of the great foundation stones of the contemporary novel of espionage and adventure with political teeth.” Other commentators have simply called it the first great modern spy novel.

Rudyard Kipling’s "Kim" appeared two years earlier and, set in India, focuses on how a young street urchin is trained for “the Great Game,” the seemingly never-ending struggle for control of Central Asia. The other early espionage classic is, of course, John Buchan’s "The Thirty-Nine Steps" (1915), the story of Richard Hannay, wrongly suspected of murder and soon on the run across Britain, eluding capture by both the police and enemy agents, and ultimately discovering the dark meaning of the code words “the thirty-nine steps.”

John Buchan would go on to write many similar pursuit thrillers -- see my earlier Library without Walls essay on his work -- but he himself judged "The Riddle of the Sands" “the best story of adventure published in the last quarter of a century.” As he went on to say in his 1926 preface to a reissue of that novel:

“It is a tale of the puzzling out of a mystery which only gradually reveals itself, and not till the very end reaches its true magnificence; but its excitement begins on the first page, and there is a steady crescendo of interest.”

Buchan adds, “As for the characters, I think they are the most fully realized of any adventure story that I have met, and the atmosphere of grey northern skies and miles of yeasty water and wet sands is as masterfully reproduced as in any of Conrad’s.”

Erskine Childers’s novel opens in the first week of September, presumably a year or two before 1903. Carruthers, a somewhat foppish young Oxford graduate working for the Foreign Office, is bored with his deskbound life. His friends have all gone off shooting or fishing for their holidays and he’s feeling left out. After all, he’s been stuck all summer in London largely because of the caprice of one of his superiors and partly because of an unnamed “cloud on the international horizon.” At just this moment, Carruthers unexpectedly receives a letter from a former university acquaintance named Davies, who invites him to go sailing around the Baltic. Davies offers further temptation with talk of some excellent duck shooting.

“The letter,” writes Carruthers, “marked an epoch for me; but I little suspected the fact as I crumpled it into my pocket.” After dithering a bit, Carruthers decides to go, though he is a bit disconcerted by Davies’s request that he bring with him, along with two rifles, rigging screws, oilskin rain gear, some Raven Mixture tobacco, a prismatic compass, and a No. 3 Rippingille stove. Somewhat resentfully, he rounds up all this gear and makes his way to Flensburg, Germany, where he is to rendezvous on September 26th with Davies and the yacht Dulcibella.

There both young men are in for a shock.

When Davies appears, he is dressed in “an old Norfolk jacket, muddy brown shoes, grey flannel trousers (or had they been white?) and an ordinary tweed cap.” Carruthers has naturally brought along proper yachting clothes, appropriate to a pleasure cruise with lots of drinks and good food and chaps to raise the anchor, trim the sails and what not. As it turns out, the Dulcibella is just a thirty-foot flat-bottomed boat, drawing very little water when the centerboard is up. Davies admits he can actually sail her alone, though life is easier and more pleasant with a companion.

Childers makes sport of Carruthers’s early days aboard the Dulcibella, and for a while the novel is almost a reprise, with a slight reduction in number, of Jerome K. Jerome’s comic "Three Men in a Boat." But gradually, as Carruthers and the reader are introduced to the intricacies of sailing a small vessel in tidal estuaries, amid shifting sand bars, the narrative begins to darken. Why did Davies want Carruthers to join him? Could it have something to do with the latter’s fluent command of German? Why does Davies repeatedly urge that they should work their way into the North Sea, where he had been sailing a few weeks earlier? His curiosity aroused, Carruthers skims through the ship’s log and discovers that the pages covering three days in early September have been torn out.

Compared to modern spy novels, "The Riddle of the Sands" develops very slowly. For much of its first third, the book seems primarily an account of in-shore sailing on the Baltic, with occasional storms for excitement. Little wonder that the novel has been regularly reprinted as a classic of nautical fiction, and long been a particular favorite of amateur yachtsmen.

Still, these early pages do chart Carruther’s education in seeing, since piloting, navigation, and general seamanship require close observation of wind, water, and weather. To a great degree, Childers’s novel revolves around detecting that which is hidden, whether a channel or a sandbar, a secret operation or a person’s true self.

One day, when all boats are confined to port because of fog, a garrulous German barge captain casually refers to how he saved Davies from disaster and likely death when, during a gale, the Dulcibella ran aground in a treacherous passage near one of the Frisian Islands. Carruthers can’t bear it any longer: What was Davies doing there? Finally, the full story comes out -- and before long the two young men, now friends, are cautiously, almost surreptitiously making their way back to the North Sea.

It will, however, prove to be far more than “a gay pursuit of a perilous quest” or one of those stories “from the six penny magazines” about a spy “with a Kodak in his tie-pin, a sketchbook in the lining of his coat, and a selection of disguises in his hand luggage.” There is, for example, the matter of the sleekly powerful yacht Medusa. And a certain girl named Clara. And a stealthy night visitor to the Dulcibella. The enthralled reader, like any good sailor watching the sea and sky, should pay close attention to everything – even those old naval histories and memoirs that Davies almost throws overboard. And hang on: The book is soon moving faster and faster.

If you look at the title page of "The Riddle of the Sands", it reads “A Record of Secret Service Recently Achieved. Edited by Erskine Childers, Author of 'In the Ranks of the C.I.V.' With Two Maps and Two Charts.” It hardly sounds like a novel at all. There’s even a preface in which we’re told that Carruthers came to Childers and related all the discoveries made on his voyages with Davies. These were duly communicated to “the proper authorities” and had served “to avert a great national danger.” But, all too typically, the government seems to have taken no long-term action. Hence, Carruthers now wishes to bring this important information to the public, and asks Childers to make the material into an entertaining narrative so as to attract a wide circle of readers. What matters most, he insists, is getting the book’s warning message across to as many people as possible.

What is that message? Childers himself was an avid small-craft sailor, with a passion for exploring the North Sea and the German coast. The maps and charts he includes are detailed views of this territory, and especially the area around the Frisian Islands and the resort city of Norderney. (An aside: Some readers may recall Isak Dinesen’s wonderful story set there in "Seven Gothic Tales," “The Deluge at Norderney.”) It doesn’t take a Sherlock Holmes to deduce that the secret involves possible conflict with Germany. As Carruthers ominously says: “She grows, and strengthens, and waits.”

In this regard, "The Riddle of the Sands" may be viewed as a distinguished example among those many contemporary novels and stories that imagine a great war in the near future. As early as 1871, George Chesney’s "The Battle of Dorking" depicted a German invasion of England, and as late as July 1914, Arthur Conan Doyle’s “Danger!” warned of England’s vulnerability to submarine attack. Even comic writers addressed the theme: In P. G. Wodehouse’s "The Swoop" (1909), an English boy scout saves his country; in Saki’s "When William Came" (1913), Germany has conquered and colonized Britain.

It is almost disconcerting, then, that in "The Riddle of the Sands" Davies frequently expresses not hatred but admiration for the Germans, as individuals and as a people, as sailors and as engineers. He even weeps at a memorial to her fallen soldiers and has nothing but praise for the kaiser, who he says works hard for his country and looks to its future. Nonetheless, Davies remains a heart-of-oak Englishman, patriotic to the core. By the end, he and Carruthers risk their lives to alert the Admiralty to...

Well, I won’t say what. But before a climax that depends upon the inexorable movement of the tide, the two friends will make a daring sea journey by night, try desperately to decipher a few enigmatic clues that may or may not refer to a mysterious salvage operation, wonder who if anyone can be trusted, shake off inscrutable enemy agents, unmask a traitor and, not least, rescue a beautiful young woman. As always in early spy fiction, hardened professionals are no match for plucky amateurs.

One last note: I haven’t said much about Erskine Childers (1870-1922), but his life is even more sensational than his novel (the only one he ever wrote), though it comes without a happy ending. Educated at Cambridge and a longtime clerk to the House of Commons, Childers served bravely in the Boer War and rose to the rank of major in World War I, earning Britain’s Distinguished Service Cross. But he was Irish on his mother’s side and eventually committed himself to the outlawed republican struggle for an independent Ireland. Captured during the civil war with a small pistol (supposedly a gift from Michael Collins), he was imprisoned as a terrorist and then, partly as an example to others, executed in 1922. He accepted his fate calmly and seems to have even welcomed his chance to die as a martyr to a cause he firmly, even fanatically, believed in. His last words were to the firing squad: “Take a step or two forwards, lads. It will be easier that way.”

Michael Dirda is a Pulitzer Prize-winning columnist for The Washington Post Book World. He is the author of the memoir An Open Book and several collections of essays. The latest, Classics for Pleasure, was published this fall.